<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .one {
            width: 100px;
            height: 100px;
            background-color: pink;
            margin-bottom: 40px;
        }
        .two {
            width: 100px;
            height: 100px;
            background-color: pink;
            margin-top: 20px;
        }
        .father {
            width: 300px;
            height: 300px;
            background-color: rgb(20, 146, 196);
            border-top: 1px solid black;
        }
        .son {
            width: 100px;
            height: 100px;
            background-color: rgb(235, 142, 35);
            margin-top: 10px;
        }
    </style>
</head>
<body>
    <div class="one"> one </div>
    <div class="two"> two </div>

    <div class="father">
        <div class="son">son</div>
    </div>
</body>
</html>